The present invention relates generally to anti-G suits, and more specifically to anti-G suit improvements increasing the body surface area compressed by the anti-G suit.
While flying simulated or actual combat maneuvers, a fighter pilot's body undergoes very high accelerations from the rapid changes in speed and direction. These accelerations are generally expressed in units of G, the force of gravity felt by a body at the earth's surface. The accelerations of greatest interest to a pilot are those that occur along the vertical +G.sub.z axis of the cockpit when the pilot pulls back hard on the aircraft control stick to accomplish a rapid climb or a fast banked turn. The pilot's oxygen-carrying blood is forced away from its regular path between the heart-lungs and the brain, and pools toward the blood vessels of the lower extremities. The heart and diaphragm tend to move lower, increasing the heart-to-eye column length and further increasing the blood pressure needed to maintain blood flow to the brain. At sufficiently high G's, the pilot's field of view narrows as blood flow to the retinas is reduced, and the pilot may finally lose consciousness from insufficient blood flow to the brain.
Pilots, and other aircrew members, fight the effects of high G's by straining maneuvers, tensing the muscles of their torso and extremities to squeeze shut the blood vessels and force blood flow to continue in the upper part of the body. An anti-G suit helps this process by covering the pilot's legs and torso with air bladders that automatically inflate during acceleration to compress the blood vessels in those regions and force blood flow to continue to the brain. An anti-G suit helps blood flow to continue in the upper part of the body by increasing blood pressure upon inflation, by reducing venus pooling of blood in the lower part of the body and by maintaining heart-to-eye distance.
A typical modern anti-G suit comprises a cutaway pair of trousers with five sewn pockets containing inflatable air bladders. One bladder covers the front of the abdomen, and one each covers the portion of each leg in front of each thigh and each calf. In addition to compressing vascular tissue, the abdominal bladder presses into the abdomen and helps hold the heart in position. The modern anti-G suit, in use virtually unchanged since World War II, evolved from full coverage liquid filled anti-G suits developed in 1939. The water-filled suit performed well, but was abandoned due to poor pilot acceptance. The water-filled suit evolved to an air filled garment in which the size of the bladders were reduced in size until they were accepted by pilots while still providing adequate protection.
Aircraft built between the 1940's and the early 1970's did not have the power to sustain high G turns without losing significant airspeed. The standard anti-G suit provided adequate protection for those aircraft. Modern high-performance jet aircraft, however, can maintain high G maneuvers to such a degree that more protection, particularly duration protection or endurance, was needed. The prior art has attempted a number of ways to increase protection. In particular, the prior art has attempted to increase the body surface area compressed by the anti-G suit without unduly compromising pilot acceptance. An example of those efforts is U.S. Pat. No. 4,674,479 to Jennings et al. which, among other improvements, added a butt strap to a conventional modern anti-G suit arranged so that when the abdominal bladder inflated, it pulled tight the butt strap to compress the aircrew member's highly vascular buttocks.
Unfortunately, despite those and other prior art improvements, there is still a need for anti-G suits that further maximize the duration a pilot or other aircrew member can withstand high G forces while maintaining a configuration that does not interfere with the aircrew members performance in the aircraft. Studies have shown that even with all the prior art improvements to date, there is still too much vascular pooling of blood in the lower extremities.
It is, therefore, a principal object of the present invention to provide an extended coverage anti-G suit that provides increased resistance against vascular pooling without sacrificing pilot acceptance.
It is a feature of the present invention that it applies pressure more uniformly than prior art anti-G suits, significantly increasing comfort for aircrew members.
It is an advantage of the present invention that it is quick and easy to put on or remove.
These and other objects, features and advantages of the present invention will become apparent as the description of certain representative embodiments proceeds.